KFRI Research Report 146

MASS REARING OF SELECTED BUTTERFLIES FOR POSSIBLE

REINTRODUCTION IN CONSERVATION PROGRAMMES

George Mathew

KERALA FOREST RESEARCH INSTITUTE PEECHI, THRISSUR

April 1998 Pages: 44

CONTENTS

Page File

Abstract i r.146.2

1 Introduction 1 r.146.3

2 Review of Literature 5 r.146.4

3 Materials and Methods 9 r.146.5

4 Results and Discussion 12 r.146.6

5 Conclusions 26 r.146.7

6 References 29 r.146.8

7 Appendix 31 r.146.9

aptive breeding of organisms for possible reintroduction in species con- C servation programmes is well recognized. Insect breeding Centers, particu- larly butterfly farms, are the major attraction in many countries. However; in India not much progress has been made on these lines. In the present study, an attempt was made to standardise a methodology for captive breeding of butterflies under Kerala conditions.

General information on the butterflies found in a gwen locality. their habitat preferences as well as factors affecting survival is very essential for the success of any captive breeding programme. Build up of infra-structure and stand- ardisation of a breeding programme for the species selected are also very important.

In this study, a general suruey was made on species found in KFRI campus at different seasons and their number monitored. Based on data gathered, the commom rose (Pachliopta aristolochiae) and the southern birdwing (Troides minos) which breed on Aristolochia indica were selected for mass rearing. Attempts to maintain their population throughout the year in the insecto was not successful mainly due to defects of the insecto and therefore attempts were made to lure butterflies into the garden by planting appropriate larval and adult host plants and by offering suitable ecological conditions through land- scaping. General facilities required for a ‘butterfly house’ are also briefly discussed.

Key words: Butterfly house, butterfly garden, conservation, Kerala. India.

i

INTRODUCTION

omestication of both plant and animal species has been practised in D many fields of human endeavor such as commerce, research and teaching. The range of domesticated species has increased considerably with the advancement of scientific knowledge . The classical examples of success- ful domestication are those of the silk worm Bombyx mori, the honey bee Apis mellifera and the medicinal leech Hirudo medicinalis (Wilson. 1971). Other species such as the fruit fly Drosophila melanogaster , locusts and the giant snail Achatina sp., have been bred for educational or research purposes.

Current estimates indicate that only 1.6 million out of an estimated total of 30 million species have been so far collected and identified. Of these, the invertebrates form an overwhelming majority of life on earth, in terms of individuals, species and biomass. Not only are invertebrates dominantly diverse but they are also the basis of most ecosystem processes. I t has been stated that if the vertebrates were to be wiped out, the World’s ecosystems would be perturbed for several years but if invertebrates were to be wiped out our planet would never recover (Wilson, 1987).

Among invertebrates, insects form the major group. According to an estimate 7,5 1,000 species of insects have been so far recored (WRI. et al , 1992). Insects are of diversified habits and may be phytophagous, predatory, parasitic or saprophytic. However, majority of insects are phytophagous feeding either on the foliage, stem or fruits. It has been stated that approximately one quarter of insects are plant feeding species (Strong et a1 1984). Roughly half of these belong to the group Lepidoptera which include the butterflies and the moths.

SIGNIFICANCE OF LEPIDOPTERA

Lepidopterous insects being highly colorful have great aesthetic value. Many species of butterflies are much sought after because of their marvellous appearance. They have also been looked upon as organisms of ecological significance since they form the primary herbivores in the ecosystem. All stages of Lepidoptera are also fed upon by various higher groups of animals like birds, bats and mammals and thus form more than one link in the food web. Butterflies and moths being important pollinators of several wild and domesticated plant species, depletion of their population could adversely affect the regeneration of plants they pollinate. As the immature stages of

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Lepidoptera are phytophagous in habits they also have great economic importance as pests of various crops of agricultural and forestry importance.

THREATS FOR SURVIVAL OF BUTTERFLIES

Ecological factors

Since butterflies are often dependent on specific host plants and have a complex life cycle, they are vulnerable to the activities of man which disturb their habitat. Land, drainage, application of fertilizers and herbicides, and mechanization have helped farmers to achieve high productivity, but these activities have affected the survival of several butterflies and their biotopes (van der Made, 1987). The Homerus Swallowtail Papilio homerus Fb. which once inhabited the 13 parishes in the island of Jamaica is currently found only in two isolated and diminishing strongholds. The principal reason for the depletion of this butterfly is due to destruction of the virgin wet rainforest habitat (Emmel and Garraway, 1990).Thus the main causes of the decline of butterflies include biotope destruction due to changed land management and the failure by several species to track the patches of their habitat that are still being generated in modern fragmented landscapes.

Local extinctions of butterfly populations during periods of unfavourable weather have also been reported. During such periods the habitat suitability also declines affecting survival of butterfly populations (Pollard, 1979; Thomas, 1980). For instance, the extinction of the black hairstreak Strymoni- dia pruni is reported to be caused by destruction of its breeding sites.There are about 12,000 species of butterflies found all over the world and if we assume that one in ten could be catergorized as threatened, then we are obliged to suspect that more than 1,200 species of buterflies could be facing extinction. It has been estimated that extinction of a single species may set in motion a chain of events, adversely affecting the survival of 10-20 other species which are related to it.

Butterfly trade

Butterflies have been objects for trade and it has been pointed out that collecting on a commercial scale can cause extinction of species (Shel- don.1925; Mc Leod, 1979). Ford (1945) has stated that the extinction of Lycaena dispar in Britain was due to over collecting. Some are of the opinion that collecting can affect only populations that are already weakened (Gardi- ner, 1974: Spooner, 1963). Since all collections are aimed at the rare and colourful species, these are the species facing maximum threat.

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PROTECTION OF BUTTERFLIES

Through legislation

In order to prevent over exploitation of various species, many countries have formulated strict measures of protection of fauna through legislation. Under the Indian Wildlife Act (GOI. 1982), 129 species have been includes schedule I and 292 species under schedule II. The act prohibits export of butterflies (dead or alive) and manufacture of decoration articles using these insects. According to section 40(2) of this act no person can acquire, receive, keep in

custody or possession any of the species included in the above schedule with out prior permission of the Chief Wildlife Warden. Although attempts'are being made to prevent illicit collection of butterflies through legislation, many cases go unnoticed.

Through habitat improvement and reintroduction

As has been stated earlier, habitat loss is another reason for the dwindling butterfly population. Creation of lost habitats for augmenting natural popu- lations and reintroduction of species has been suggested for conservation of butterflies. However, this method has rarely been explored as a means to re-establish wild poulations on account of the prohibitive costs (Hughes and Bennet, 1991).

Successful reintroduction programme requires establishment of appropriate technology and also formulation of a long term conservation programme for rare and endagered species. This is possible only through the establishment of specific Centers of Research and Development. At present, insect farming has been practised successfully for a few species like honey bees and silk moths and there are several research Institutions in India to cater to the R & D requirements of farming these insects. Butterfly farming Centers are not yet established in India, although in several countries like Malaysia,Tai- wan, Papua New Guinea, Philippines and Sri Lanka such Centers are playing a major role in the conservation of local fauna. Such Centers may also be useful to impart environmental education to children and public (Khoshoo, 1984).

Although 269 international programmes are currently involved with species conservation, only one is concerned with invertebrates (Hughes and Bennett, 1991). It has been estimated that 2250 invertebrates (compared with 689 mammals, 1047 birds, 191 reptiles and 63 amphibians) are in danger of extinction (IUCN, 1990). With a view to promote conservation of invertebrates

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IUCN has formed various 'specialists groups' which undertake captive breed- ing programmes. In India, very few attempts have been made in this direction except for the recent initative by the Zoo Outreach Organization in Coimba- tore.

SCOPE OF BUTTERFLY CONSERVATION IN INDIA

India, with its diversifled habitats is very rich in its butterfly fauna with over 1430 species of butterflies reported from all over the country. But the advancements in human civilization has affected the natural habitats of many species of butterflies threatening their survival. As a result, the range of many species are very much restricted. According to Talbot (1939, 1947) and Wynter - Blyth (1957), as much as 520 species (including subspecies and races) constituting over 30% of known butterflies are rare. Even in the natural habitats, many species having highly specific ecological requirements are facing threats due to slow changes in the ecosystem as revealed by a study in the Silent Valley National Park where of the 100 species observed, about 13 were extremely rare (Mathew, 1990).

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REVIEW OF LITERATURE

BUTTERFLY FAUNA OF INDIA

he Order Lepidoptera which is the second largest insect Order is esti- Tmated to contain over 1.40,000 species of which 12,000 are butterflies. Out of these, about 1430 species of butterflies under 10 families have been recorded from the Indian sub region (Talbot. 1939, 1947, D'Abrera, 1982, '85, '86). In Kerala, about 320 species of butterflies have so far been reported. Due to destruction of natural habitats, a number of these butterflies are to be found only in the forests. A recent study in Nilgiri Biosphere Reserve has indicated survival of several endangered and rare species of butterflies in this region (ZSI, 1988; Larsen, 1987, 1988; Mathew, 1990). With the current rate of disturbance to natural ecosystems, many species are likely to be phased out by the turn of the century unless urgent and active remedial action is initiated. Brief account of the various families well represented in Kerala are given below:

Papilionidae

They are popularly known as 'swallow tails' on account of the tail-like extension of their hind wings. In size, they range from small to very large and are beautifully colored. Of about 217 species (including sub species), 18 species are commonly found in Kerala. The larvae of some papilionids are known to develop on plants belonging to Aristolochiaceae (Aristolochia indica, Bragantia sp.): Anonaceae (Anona sp., Polyalthia sp.); Lauraceae (Machilus macarantha, Listea floribunda, Cinnamomum zeylanicum, Actinodaphne sp.) and Rutaceae (Citrus sp., Aegle marmelos. Atlantia sp., Glycosmis pentaphylla and Xanthoxylum rhetsa).

The southern bird wing (Troides minos), the malabar rose (Pachliopta jophon), the common rose (P. aristolochiae). the common mime (Chilasa clytia), the blue mormon (Papilio polymnestor) are some common papilionid butterflies found in Kerala.

Pieridae

Commonly known as whites or yellows, most of them are fond of sunshine and are found to frequent banks of streams or puddlles in aggregations. Of the 100 species reported from India, 35 species are found in Kerala.

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The larvae develop on plants belonging to the families, Berberidaceae (Berberis sp.). Capparidaceae (Capparis sp.. Crataeva sp, Cadaba sp. and Maerua sp.); Cruciferae (Cabbage); Euphorbiaceae (Hemicyclia sp.) Legumi- nosae (Cassia sp., Albizia sp., Wagatea sp.. Poinciana sp.. Butea sp.); Loranthaeceae (Loranthus) as well as Salvadoraceae (Salvadora sp.).

The common jezbel (Delias eucharis) , the common wanderer (Pareronia valeria), the lemon emigrant (Catopsilia pyranthe) and the common emigrant (Catopsilia pomona) . the mottled emigrant (Catopsilia pyranthe) and the common grass yellow (Eurema hecabe) are the common pierids found in Kerala.

Danaidae

These are relatively hard butterflies that are unpalatable to predators on account of their feeding on plants containing alkaloids. The caterpillars develop mostly on plants belonging to Apocyanaceae (Agonosma sp., Vallaris sp.. Ichocarpis sp., Marsdenia sp. and Raphistemma sp.): Rubiaceae (Alleo- phania sp.); Asclepiadaceae. Caesalpiniaceae and Utricaceae (Ficus spp.).

There are 77 species occurring in the Indian subcontinent of which 14 species are found in Kerala. The Malabar tree nymph (Idea malabarica), the nilgiri tiger (Parantica nilgiriensis), the blue tiger (P. limniace) . the glassy blue tiger (P. aglea), the striped tiger (Danus genuita) , the plain tiger (D. chrysippus) and the common crow (Euploea core) are certain species found in Kerala.

Satyridae

These butterflies are predominantly shade loving species and are found mostly in dense forests or such situations. They are mostly brownish in color and occur in large numbers frequenting over-ripe fruits or sappy exudation of plants. Some species exhibit seasonal variations as dry and wet season forms. Of about 330 species reported from the Indian subcontinent, 30 are found in Kerala which include the common bush brown (Mycalesis perseus), the white bar bush brown (M. anaxias), the common tree brown (Lethe rohria) and the common five ring (Ypthima baldus) . Larvae develop on palms, grasses and bamboos.

Amathusidae

Members of this family, generally known as jungle queen, palm kings, duffers etc., are large sized and sombre colored. The morpho butterflies of South

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America are well known for their brilliant iridescent colors. They rarely venture out in bright sunlight and are often confined to thick forests. Adults feed on over-ripe fruits and sappy exudation of trees. Their immature forms feed on leaves of bamboos or palms.

The species found in the lndo-Malayan region are very colorful and there are about 50 species in the Indian sub region of which at least two species belonging to Discophora are common in Kerala.

Nymphalidae

These butterflies are noted for their beautiful coloration, wing pattern and flight. They are popularly known as raja, nawab. baron, duke, duchess, commodore, sergeant, sailor, map, oakleaf, pansy, leopard, lacewing etc.

Nymphalid butterflies vary considerably in color being bright to brilliant. In size they range from 25-130 mm. Sexual dimorphism is present in some species while in others seasonal forms are present. A few species are known as mimics of danaids and there by gain protection. There are over 400 species of nymphalids in the Indian sub region, of which 48 species occur in Kerala. The common bush brown (Moduza procris), the common sailor (Neptis hylas), the great egg fly (Hypolimnas bolina), the yellow pansy (Junonia hierta). the lemon pansy (J. lemonias), the baron (Euthalia garuda) and the tamil yeoman (Cirrochroa thais) are some of the species commonly found in Kerala.

The immature stages feed on Tamarindus indica, Caesalpinia sp.. Adenan- thera pavonina, Albizia spp., Mangifera indica, Anacardium occidentale, Hald- ina cordifolia, Xylia xylocarpa, Olea dioica etc.

Lycaenidae

They are predominantly blue in colour and are generally small in size. The immature stages mostly feed on Acanthaceae (Strobilanthus sp.). Amaran- thaceae (Amaranthus sp.), Cycadaceae (Cycas sp.). Leguminosae ( Abrus sp., Albizia sp., Cassia sp., Xylia sp.). Utricaceae (Ficus sp.) and Verbanaceae (Clerodendron sp. and Lantana sp.). There are about 650 species in India, of which 35 are known from Kerala which include the gram blue (Euchrysops cnejus), the common cerulean (Jamides celeno), the metallic cerulean (J. alecto) and the common pierrot (Castalius rosimon).

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BUTTERFLY FARMING

Butterfly farming is closely linked with establishment of ‘butterfly houses’. Perhaps the roots of this technique are in Britain where the ‘butterfly house’ exhibit has grown from two different lepidopteral industries: first from breeders of European butterflies who began breeding exotic tropical species and secondly from the silk industry where some breeders began displaying certain exotic silk moths to visitors.

From the merger of these two activities and the provision of large glass enclosures, there developed the ‘butterfly house’ - which emerged as a public attraction in the 1960s. The first butterfly farm- the Guernsey Butterfly Farm was established in the U.K. in the 1960s. The 1980’s saw a massive expansion of the business with over 40 facilities being reported by 1986 . A survey conducted in 1987 in 26 butterfly houses in UK has indicated that 306 species of butterflies were used in the butterfly houses with 26-75 species being kept at any one time (Collins, 1987).

The concept of captive breeding is also relevant in species conservation programmes. On occasions when a species is threatened with extinction due to destruction of its habitat and absence of other suitable sites to which it could be transferred , there is a need to maintain stocks in captivity for use in future reintroductions (Morton, 1983). At Wood Walton Fen in Britain, for example, a free living population of the Dutch race of the large copper butterfly Lycaena dispar batavus is supplemented annually by specimens reared in captivity (Nature Conservancy Council, 1977). The concern for the conserva- tion of butterflies has led to the formation of the IUCN specialist group on butterflies.

Thus, butterfly farming is a novel technique which simultaneously meets commercial demands for specimens with out affecting wild populations, puts cash into the local economy and (probably most important) fosters local interest and commitment to the conservation ethic. As a commercial enter- prise and as a conservation oriented programme, butterfly farming is highly promising. Butterfly farming is beneficial in conservation of tropical forests and also provides rural economics with income (Pearson. 1992).

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MATERIALS AND METHODS

n existing insectory (8m x 5m x 5m) covered with fine steel netting and A provided with a double door was made use of for rearing purpose (Figs. la and lb). Within the cage appropriate larval host plants were maintained to facilitate oviposition by the butterflies released. In addition to this, provision was also made to keep diluted sugar solution for sustaining butterflies.

An area of approximately 0.5 ha surrounding the insectory was landscaped so as to produce different habitats such as dense vegetation (Figs. 2a & 2b), open areas, bushes etc., in order to attract local butterflies having different habitat preferences. The species planted in this area include Aristolochia indica, Murraya koenigi Crotalaria retusa Lantana camara, Clerodendron capitatum Cassia sp.. as well as Citrus sp., which serve as host plants of several butterflies like Pachliopta aristolochiae, Papilio demoleus, Danaus genuita and Tirumala limniace leopardus (Appendix- I). Regular observations were also made on butterflies visiting various plants.

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---Fig. I. a. View of the butterfly house in KFRI campus

b. Interior o~the butterfly house with A~tolochta.indic~ grownfor breedmg the common rose, PathllOpta aristaloClitaeI

10

"

w

~Fig. 2. a. View of the butterfly garden in KFRI campus containing

flowering plants like Lantana camara and Clerodendronpaniculatum

b. Crotalaria grown into hedg~s for attracting danainebutterflies

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RESULTS AND DISCUSSION

Papilionidae

t took nearly two years for establishing the plants in the insectory and in I the surrounding area. With the establishment of plants, various butterflies started to frequently visit the area leading to the formation of a small local population.

Family/species Plant host Remarks

BUTTERFLIES OBSERVED IN THE BUTTERFLY GARDEN

Tros hector Lin.

Pachliopta aristolochiae Fb.

A list of butterflies, with details of their number and occurrence pattern are given in Table 1. Altogether, 1 1 species of butterflies belonging to the families

Several individuals feeding at flowers

Euploea core core Cramer

Table 1. List of butterflies recorded from the butterfly garden established at Peechi

Danaidae

Cramer

Tirurnala limniace leopardus Butler

Danaus genuita genuita Crotalaria retusa 20 to 30 butterflies aggregating on foliage

~

Papilio paris Moore

Eurerna blanda Boisd.

Pieridae

P. polymnestor parinda Moore

A few butterflies (2-3 nos.) frequenting flower heads of L. camara and Cassia sp.

Clerodendron paniculatum, flowerheads in the morning

1 or 2 individuals visiting

P.polytes Cramer

P.demoleus Lin. 11

I, I Troides minos Cramer I I I

Danaidae I

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Papilionidae, Danaidae and Pieridae were observed in the study area. The flower heads of Clerodendron paniculatum and Lantana camara were found to be very much preferred by butterflies belonging to Papilionidae and Pieridae. The danaids Danaus genuita, Tirumala limniace and Euploea core were found to aggregate in large numbers on the foliage of Crotalaria retusa. These butterflies were observed to lacerate the leaf surface by scratching with the front tarsal claws and then lick the exuding sap. The lacerated leaves later withered. Up to 20 butterflies were noted to feed gregariously on a single plant and heavy incidence of butterflies led to the wilting of plants. Danaid butterflies are already reported to feed on plants containing alkaloids. Caterpillars of an arctiid Argyria sp. were found to develop on foliage of C. retusa occasionally causing die-back of crotalaria seedlings (Figs. 3a & 3b).

An evaluation of the establishment of various butterflies in the study area was also made by examining the larval host plants for the presence of their immature stages. The hedges of Aristolochia indica contained eggs, larvae and pupae of the common rose Pachliopta- aristolochiae (Fig. 4a) and of the southern bird-wing Troides minos (Fig. 4b). Similarly, the immature stages of the lime butterfly Papilio demoleus (Fig. 5a) was noted on Citrus sp., and Murraya koenigi; Moduza procris on Mussaenda frondosa and Euploea core on Ficus glomerata. Observations were also made on the occurrence of butterflies in the garden during the various months (Table 2). Data gathered has shown that, in general, the number of butterflies present was high during the months September to December. The butterflies showed a reduction in population during in summer (March-May).

Seven species of papilionids including Papilio paris, P. polymnestor; (Fig. 5b) P. dernoleus; the danaids Pachliopta aristolochiae, Parantica nilgiriensis and Euploeacore were observed quite frequently in the garden. The pierids Eurema hecabe and Catopsilia pornona (Fig. 6a and 6b) were also found in small numbers feeding at the flowers of Lantana camara and Cassia sp.

BUTTERFLIES RELEASED IN THE FIELD CAGE

Preliminary attempts to farm butterflies in captivity were made by releasing both the adult and immature stages of certain commonly available butterflies like Troides minos, Papilio demoleus and Pachliopta aristlochiae in the insec- tory, where appropriate larval host plants of each of these butterflies (Citrus sp.. Aristolochia indica etc.) have been established. Water as well as diluted sugar solution were kept in separate containers for feeding the butterflies.

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Fig. 3. a. Close-up of Crotalwia retusa showing a caterpillar of Argyriasp. (Arctiidae).Inset: The moth

b. Crotalaria retusa in bloom. Both leaves and flowers attractand sustain various danaine butterflies

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~

"

:"'

Fig. 4. a. The crimson rose, Pachliopta aristolochiae. Inset: Larva and

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pupab. The southern bird wing. Troides minos. Inset: Larva and

pupa

.

~

Fig. 5. a. The lemon butterfly, Pdpilio demoleusb. The blue mormoJ1 Papiliopolymnestor

16

"

01

"

Fig. 6. a. The white. Catopsilia pomonab. The grass yellow. Eurema hecabe

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Table 2. Butterflies observed in the garden during various mmonths

I Stage Host plant Butterfly species year and month of observation

Mav It

Larva A. indica Tros hector August Troides rninos Adult Clerodendron

September Euploea core Adult (aggregation) Crotalaria retusa capitatum

Parantica nilairiensis

I Adult (aggregation) Crotalaria retusa

October Euploea core Adult (aggregation) Crotaluria retusa Parantica Adult (aggregation) Crotaluria retusa nilgiriensis

aristolochiae Papilio demoleus Larva & adult Citrus sp. Papilio paris Adult Clerodendron

November Pachliopta Adult (aggregation) Aristolochia indica

paniculatum December Pachliopta Adult (aggregation) Aristolochia indica

aris tolochiae 1997 Pachliopta Larva Aristolochia indica January aristolochiae February Pachliopta Larva

aristolochiae Mussaenda I Moduza procris I Larva frondosa

March Pachliopta 1 Aristolochia indica aris tolochiae

April Mav

June Paran tica nilairiensis

1 Adult (aggregation) Crotalaria retusa

I Euploea core I I July 1 Parardica I I I nilgiriensis

I Euploea core

The butterflies thus released survived for about a weak but no instance of mating and egg laying was noticed. Perhaps the area available within the insectory was not sufficient to induce mating response. The butterfly farms established in Malaysia had large areas (covering over 100m2) under enclo- sure so as to provide as much natural space as possible. Even in this case,

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the natural build up of butterflies on the host plants was not satisfactory and butterflies had to be introduced into the cage at intervals in order to maintain the population within the cage. Details of butterflies released into the cage area given in Table 3.

Tros hector

Table 3. Details of butterflies released in the insectory

Larva . 7 Nos. 19-7-96 Pupation from 21-7-96 to 23-7-96. Adult emergance from 1-8-96 to 3-8-96

Remarks

Euploea core

Pachliopta aristolochiae

Adult 4 Nos. 22-7-96 Found dead on 26-7-96

Larva 1 No. 30-10-96 Pupated on 5-11-96. Adult emergance on 15-11-96

Larva 10 Nos. Pupation from 28- 10-96 to 30- 10-96 Adult emergance from 24- 10-96 5-11-96 to 8-11-96

Troides minos Larva 2 Nos. 2-7-97 Pupated on 15-7-97. Adult

Pupa 1 No. 21-7-97 Adult emergance on 28-7-97

emergance on 2 1-7-97

CONSTRAINTS FOR BREEDING BUTTERFLIES IN CAPTIVITY

Being a pilot study, attempts were made to evaluate the various require- ments for the successful breeding of butterflies in field cages. The constraints faced in this study are discussed below.

Out door cage

In the present study, an insectory in the KFRI campus was made use of. Although butterflies were reared in the laboratory in rearing bottles and oocasionally in small cages, the dimension of cage was found to be important for the success of the breeding programme particularly when the intention is to maintain butterflies in a natural setting.

Standardised strategy for breeding

General information on the biology and ecology of butterflies to be bred, natural mortality factors as well as availability of appropriate larval and adult

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host plants are essential for the success of any breeding programme. In the present study, selected butterflies were initially bred in small containers in

the laboratory prior to release in the field cage. Predation by lizards and infestation by micro-organisms were the major reasons for the decline of population maintained in the field cage. Instances of 'inbreeding' leading to a loss of vigor due to loss of heterozygosity and fixation of homozygous alleles have been reported in continued breeding programmes. Since most species of butterflies have more than one host plants, care should be taken to select the most appropriate host.

GENERALISED PLAN OF A BUTTERFLY HOUSE

A typical butterfly house should have facilities to breed various species in captivity and also to display preserved material in order to create public awareness on species conservation (Fig. 7). A detailed account of facilities required for a butterfly house are given below.

Display area

Insects particularly butterflies form excellent materials for exhibits and hence should be displayed in the front area. The exhibits should be so organised as to give general information on species diversity and its role in ecosystem functioning. Both native and exotic fauna may be exibited (Fig. 8). Commer- cial products made out of insects, souvenirs etc., also may be exhibited in this area.

Sales counter

Souvenirs and curios made out of insects, plastic models, charts, books, stickers, posters, paintings, insect study and collection kits, T-shirts, badges, bags etc.. form excellent material for sale. The sale proceeds from such items together with gate collections will bring good revenue to make the butterfly house self supporting.

Butterfly release area

The butterflies are generally reared in separate rearing rooms either on their larval host plants or on artificial diets. The butterflies are subsequently left in the release area which is open to the public.

The release area should be developed with care so as to offer conditions suited for the butterflies released (Fig. 9). It may be either a simple net house or a

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glass house with adaptations to regulate temperature, humidity, air move- ment and day length. Temperature and relative humidity are the most important factors to be taken care of. Temperature ranging from 20-30o seems to be preferrable for most tropical butterflies. Excessive humidity may lead to development of fungal attack. Most species also thrive best at a relative humidity exceeding 90 percent. In addition to these, slight air currents will stimulate them to move about leading to a high frequency of feeding and courtship.

In order to offer conditions for mating and egg laying, appropriate larval and adult host plants should be kept in the release area. As nectar and pollen from this source alone may not be sufficient, provision may also be made for providing artificial food. Generally, sugar solution as soaked cotton wads is kept. In some butterfly houses, the solution is kept in a tube. Colored ‘corolla’ or plastic flowers are kept around the tube to attract butterflies. Powdered pollen available from bee keepers may also be kept on the ‘corolla’. Besides these. over-ripe fruits dusted with sugar, carrion. dung etc., may also be used depending on the species. Sufficient care should be taken to keep the solution, containers and ’corolla’ disease free. For this, these may be rinsed in 5% sodium hypochlorite solution before use.

Most of the commercial butterfly houses in the west are walk through heated glass houses fitted with special halide lamps for lighting as daylight is completely cut off. For tropical conditions such arrangements may not be required. Butterfly houses in Malaysia for example, are only enclosures with simple provisions for air regulation and humidity control and do not use much sophesticated techniques as in the west.

PREPARATION OF CURIOS

In many countries like Papua New Guinea, preparation of ’curios’ using dead insects has grown into a cottage industry. The wings of many butterflies are very attractive and hence even bits or fragments of wings can be made use of in the preparation of various art works. There is strong criticism in the preparation of such articles mainly due to the fear that this may lead to exploitation of local fauna and may affect even the survival of the species. What is suggested here, is to make use of dead insects that become available in an insectory during routine breeding programmes. It is strongly recom- mended that no attempt should be made to rear the insects merely for commercial utility. Some general techniques for processing dead butterflies or fragments are discussed below.

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Dry mounts

Insects that are not mutilated can be spread on boards and allowed to dry in the air or in the oven at 50-55oC. Such dried material will retain its shape and can be assembled on a board and framed or retained in attractive display boxes. Appropriate fumigants -like naphthalene pellets - may be kept inside the boxes to prevent attack by small insects like psocids. Another problem with dry mounts is fungal attack during wet seasons. If the box is air tight, this problem can be managed to some extent.

Plastination

This is a technique used for preserving biological specimens by embedding in a polyester or epoxy resin. For getting best results the material used should be fresh. The procedure for plastination is as follows. At first. the material is subjected to dehydration by freeze drying in vacuum. This can be achieved by leaving the material in a desicator to which is attached a vacuum pump. Treatment in cold acetone at -25oC will also enhance dehydration. The material is then soaked in a polyester resin to replace the tissue fluid. As the chemical will get polymerised at room temperature. care should be taken to keep the material in the desired shape and after polymerisation the shape can not be altered. The impregnated material is then treated with a hardener or catalyst to hasten the drying of the resin.

Mica-get embedding

This technique is similar to plastination, the only difference being that the material is embedded in a thick film of polyester resin. For this, a glass or mica container with detachable sides is taken into which the resin is slowly added to about 1/4 th of its depth. The dried and set material to be embedded is then kept over the surface. The resin is continuously added till the whole material is thoroughly embedded. While adding the resin care should be taken to prevent formation of air bubbles. Also, the resin should be added with least disturbance so that the material will not lose its natural shape. In order to hasten quick setting of the resin, a catalyst is also added after embedding. When completely dry, the block may be polished using machine.

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CONCLUSIONS

aptive breeding of butterflies has economic as well as ecological implica- C tions as detiled below.

AS A BUSINESS

In many countries such as Papua New Guinea, Britain and Malaysia, butterfly farming has proven to be a sound, economically viable rural industry. Papua New Guinea's is a successful model that can be readily adopted to other tropical developing countries (Anon., 1983; Hutton, 1985). In that country, there are several village farming and collecting units particularly in areas that are handicapped for the usual agricultural activities, or livestock mainte- nance. Butterflies are bred in these areas with minimal forest disturbance.

Current estimates indicate that there are between 50 and 60 butterfly houses attracting five million visitors annually, in Britan. Millions of butterflies are sold as specimens or as displays. I t has been stated that the gate collections alone exceeded i€ 5 million in Britain (Collins, 1987).

AS A TOOL IN CONSERVATION AND ENVIRONMENTAL EDUCATION PROGRAMMES

Invertebrates which form the majority of the life forms on earth have been ignored until recently in zoo education and conservation programmes. During the past decade 'butterfly houses' have become very popular in several countries attracting millions of visitors.

In most environments, invertebrates are more accessible than vertebrates and they offer insights into the dynamics of ecological processes that can raise public awareness and enjoyment (Collins, 1987). The butterflies which are very colorful and attractive rival the most beautiful of the tropical fish, flowers and birds. Butterfly houses can thus promote awareness of the vital ecological roles played by invertebrates and particularly the need to conserve invertebrates as important natural resources.

Captive breeding and maintenance of stock for reintroduction is a method applied in vertebrate conservation. The possibility of invertebrate conserva-

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tion on the same lines have been suggested by several workers but largely ignored (Cooper, 1986, Morton, 1983). Pyle (1976) states that such measures should be regarded as the last resort. Introduction of species into new areas had also aroused much controversy. Such action, it is stated, would be justified only when a species has become locally extinct or when a species is facing threat of extiction due to habitat destruction.

Several instances of reintroduction of butterflies are known such as the introduction the large copper butterfly Lycaena dispar Haw. batavus Obth. into Woodwalton Fen during 1927 to replace L. dispar Haw. which became extinct towards the middle of the 19th century (Nature Conservancy Council, 1977). Similarly, the heath fritillary Mellicta athalia, which became extinct in Essex in about 1890 was reintroduced in the Hadleigh Woods with success (Luckens, 1980). Similarly attempts were also made to introduce the swallow- tail butterfly Papilio machaon britanicus at Wicken Fen in 1975. However, such introductions are terribly expensive since all infrastructural facilites for breeding and maintenance of populations have to be built up. Establishment of a Captive Breeding Center is therefore very essential for the succes of such programmes.

Perhaps the most important step in conservation should be legislation against collecting for trade particularly with regard to species that are rare. For this, information on the local fauna , the population density of various species as well as the various natural mortality factors affecting species survival should be known. Only detailed faunistic surveys can bring out these details.

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